The 31-year-old Doheny, who has now won all of his 20 pro fights, suffered cuts under both eyes early on in the 12-round bout at Korakuen Hall. Despite that, the No. 1 ranked contender stayed on the attack throughout in a battle of southpaws.

The 28-year-old Iwasa fell to 25-3. He was making the second defense of the title he won last September.

The three judges scored the fight this way: 115-113, 116-112 and 117-112.